[http://rvm.beginrescueend.com/ RVM] (Ruby Version Manager) is a command line tool which allows us to easily install, manage and work with multiple [[Ruby]] environments from interpreters to sets of gems.

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[[de:RVM]]

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[http://rvm.io/ RVM] (Ruby Version Manager) is a command line tool which allows us to easily install, manage and work with multiple [[Ruby]] environments from interpreters to sets of gems.

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There exists a similar application that you may also want to consider: [[rbenv]].

== Installing RVM ==

== Installing RVM ==

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The upstream instructions for installing RVM should just work. The install script is aware enough to tell you what packages you need to install on Archlinux to make different rubies work. This usually involves gcc and some other stuff needed to compile ruby.

The upstream instructions for installing RVM should just work. The install script is aware enough to tell you what packages you need to install on Archlinux to make different rubies work. This usually involves gcc and some other stuff needed to compile ruby.

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As an observation, '''installing RVM with gem is not recommended anymore'''. This article uses the [http://rvm.beginrescueend.com/rvm/install/ recommended documentation] with minor tweaks to make work on Archlinux.

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As an observation, '''installing RVM with gem is not recommended anymore'''. This article uses the [http://rvm.beginrescueend.com/rvm/install/ recommended documentation] with minor tweaks to make it work on Archlinux.

=== Pre-requisites ===

=== Pre-requisites ===

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Use the script that rvm docs recommends to install. Make sure to run this script as the user for whom you want RVM installed (i.e. your normal user that you use for development).

Use the script that rvm docs recommends to install. Make sure to run this script as the user for whom you want RVM installed (i.e. your normal user that you use for development).

After the script has finished, add yourself and your users to the 'rvm' group. (The installer does not auto-add any users to the rvm group. Admins must do this.) For each one, repeat:

After the script has finished, add yourself and your users to the 'rvm' group. (The installer does not auto-add any users to the rvm group. Admins must do this.) For each one, repeat:

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$ sudo usermod -a -G rvm <user>

$ sudo usermod -a -G rvm <user>

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'''Group memberships are only evaluated at login time'''. Log the users out, then back in. You too: close out your current shell or terminal session and open a new one. (You may attempt reloading your ~/.bash_profile with the following command:

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'''Group memberships are only evaluated at login time'''. Log the users out, then back in. You too: close out your current shell or terminal session and open a new one. (You may attempt reloading your ~/.bash_login with the following command:

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$ source ~/.bash_profile

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$ source ~/.bash_login

However, closing out your current shell or terminal and opening a new one is the preferred way for initial installations. Alternatively, you can use the "newgrp rvm" command and check with "id" to see whether the shell has picked up the new group membership of your user)

However, closing out your current shell or terminal and opening a new one is the preferred way for initial installations. Alternatively, you can use the "newgrp rvm" command and check with "id" to see whether the shell has picked up the new group membership of your user)

RVM will be automatically configured for every user on the system (in opposite to the single-user installation); this is accomplished by loading /etc/profile.d/rvm.sh on login. Archlinux defaults to parsing /etc/profile which contains the logic to load all files residing in the /etc/profile.d/ directory.

RVM will be automatically configured for every user on the system (in opposite to the single-user installation); this is accomplished by loading /etc/profile.d/rvm.sh on login. Archlinux defaults to parsing /etc/profile which contains the logic to load all files residing in the /etc/profile.d/ directory.

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$ rvm is a function

$ rvm is a function

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If you receive rvm: not found, you may need to source your ~/.bash_profile (or wherever you put the line above):

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If you receive rvm: not found, you may need to source your ~/.bash_login (or wherever you put the line above):

Installing RVM

The install process is very easy, and is the very same for any distro, including Archlinux. You have two choices, one system-wide, another as a user. The first is for production servers, or if your are alone on your machine. You'll need root privileges. The second is the recommended for multiple users on the same machine (like a development test box). If you do not know which to choose, start with a single user installation.

The upstream instructions for installing RVM should just work. The install script is aware enough to tell you what packages you need to install on Archlinux to make different rubies work. This usually involves gcc and some other stuff needed to compile ruby.

As an observation, installing RVM with gem is not recommended anymore. This article uses the recommended documentation with minor tweaks to make it work on Archlinux.

Pre-requisites

Before starting, you will need the following to get the installation process going:

$ pacman -S git curl

Single-user installation

Note: This will install to your home directory only (~/.rvm), and won't touch the standard Arch ruby package, which is in /usr.

For most purposes, the recommended installation method is single-user, which is a self-contained RVM installation in a user's home directory.

Use the script that rvm docs recommends to install. Make sure to run this script as the user for whom you want RVM installed (i.e. your normal user that you use for development).

After the script has finished, add yourself and your users to the 'rvm' group. (The installer does not auto-add any users to the rvm group. Admins must do this.) For each one, repeat:

$ sudo usermod -a -G rvm <user>

Group memberships are only evaluated at login time. Log the users out, then back in. You too: close out your current shell or terminal session and open a new one. (You may attempt reloading your ~/.bash_login with the following command:

$ source ~/.bash_login

However, closing out your current shell or terminal and opening a new one is the preferred way for initial installations. Alternatively, you can use the "newgrp rvm" command and check with "id" to see whether the shell has picked up the new group membership of your user)

RVM will be automatically configured for every user on the system (in opposite to the single-user installation); this is accomplished by loading /etc/profile.d/rvm.sh on login. Archlinux defaults to parsing /etc/profile which contains the logic to load all files residing in the /etc/profile.d/ directory.

Before installing gems with multi-user rvm, make sure that /etc/gemrc does not have the line "gem: --user-install". If it does you need to comment it out otherwise the gems will install to the wrong place.

You only use the sudo command during the install process. In multi-user configurations, any operations which require sudo access must use the rvmsudo command which preserves the RVM environment and passes this on to sudo. There are very few cases where rvmsudo is required once the core install is completed, except for when updating RVM itself. There is never a reason to use sudo post-install. rvmsudo should only be needed for updating with

$ rvmsudo rvm get head

A cautionary action

In order to prevent the installation breakage by this cause, you may add this configuration to your /etc/sudoers file:

Post Installation

If you receive rvm: not found, you may need to source your ~/.bash_login (or wherever you put the line above):

$ . ~/.bash_login

Check if the rvm function is working:

$ rvm notes

Finally, see if there are any dependency requirements for your installation by running:

$ rvm requirements

(Follow the returned instructions if any.)

Very important: whenever you upgrade RVM in the future, you should always run rvm notes and rvm requirements as this is usually where you will find details on any major changes and/or additional requirements to ensure your installation stays working.

Some extras

You may put in your ~/.bashrc the following lines to get some useful features:

The ASCII arrow indicates which environment is currently enabled. In this case, it is Ruby 1.8.7. This could be confirmed by running:

$ ruby --version
ruby 1.8.7 (2010-01-10 patchlevel 249) [i686-linux]

Gemsets

RVM has a valued feature called gemsets which enables you to store different sets of gems in compartmentalized independent ruby setups. This means that ruby, gems and irb are all separate and self-contained from the system and each other.

Creating

Gemsets must be created before being used. To create a new gemset for the current ruby, do this:

$ rvm use <ruby_version>
$ rvm gemset create <gemset_name>

Alternatively, if you prefer the shorthand syntax offered by rvm use, employ the --create option like so:

$ rvm use <ruby_version>@<gemset_name> --create

You can also specify a default gemset for a given ruby interpreter, by doing:

$ rvm use <ruby_version>@<gemset_name> --default

Using

To use a gemset:

$ rvm gemset use <gemset_name>

You can switch to a gemset as you start to use a ruby, by appending @<gemset_name> to the end of the ruby selector string:

$ rvm use <ruby_version>@<gemset_name>

Notes

When you install a ruby environment, it comes with two gemsets out of the box, their names are default and global. You will usually find in the latter some pre-installed common gems, while the former always starts empty.

A little bit about where the default and global gemsets differ: When you do not use a gemset at all, you get the gems in the default set. If you use a specific gemset (say @testing), it will inherit gems from that ruby's @global. The global gemset is to allow you to share gems to all your gemsets.

Gems!

Within a gemset, you can utilize usual RubyGems commands

$ gem install <gem>

to add,

$ gem uninstall <gem>

to remove gems, and

$ gem list

to view installed ones.

If you are deploying to a server, or you do not want to wait around for rdoc and ri to install for each gem, you can disable them for gem installs and updates. Just add these two lines to your ~/.gemrc or /etc/gemrc:

install: --no-rdoc --no-ri
update: --no-rdoc --no-ri

Listing

To see the name of the current gemset:

$ rvm gemset name

To list all named gemsets for the current ruby interpreter:

$ rvm gemset list

To list all named gemsets for all interpreters:

$ rvm gemset list_all

Deleting

This action removes the current gemset:

$ rvm gemset use <gemset_name>
$ rvm gemset delete <gemset_name>

By default, rvm deletes gemsets from the currently selected Ruby interpreter. To delete a gemset from a different interpreter, say 1.9.2, run your command this way:

$ rvm 1.9.2 do gemset delete <gemset_name>

Emptying

This action removes all gems installed in the gemset:

$ rvm gemset use <gemset_name>
$ rvm gemset empty <gemset_name>

RVM

Updating

To upgrade to the most recent release version:

$ rvm get latest

Upgrading to the latest repository source version (the most bugfixes):

$ rvm get head

Remember to use rvmsudo for multi-user setups. Update often!

Uninstalling

Executing

$ rvm implode

is going to wipe out the RVM installation —cleanly—.

Further Reading

This is just a simple introduction to switching ruby versions with RVM and managing different set of gems in different environments. There is lots more that you can do with it! For more information, consult the very comprehensive RVM documentation. This page is a good place to start.

Troubleshooting

You will need to take care with rvm installations, since ArchLinux is very well updated, and some earlier ruby's patchlevels do not like it. RVM many times do not choose the latest patchlevel version to install, and you'll need to check manually on the ruby website, and force RVM to install it.

"data definition has no type or storage class"

This appears to be specific to 1.8.7, but if you get this error while compiling the following steps will fix your problem:

The patchlevels >p378 have a problem with gem paths, when $GEM_HOME is set. The problem is known and fixed in 1.9.2. (http://redmine.ruby-lang.org/issues/3584). If you really need 1.9.1 please use p378.